/*ID样式*/
/*ID样式在整个HTML文档中尽量保持唯一*/
#t3{
    background-color: aqua;
    font-size: 30px;
    font-weight: bolder;
    font-family: 隶书;
}
/*组合样式*/
div p{
    color: darkblue;
}

body{
    margin: 0;
    padding: 0;
    width: 100vw;
    height: 100vh;
}
div{
    position: relative;
    float: left;
}
#div_container{  /*最外层*/
    height: 100%;
    width: 80%;
    border: 1px solid red;
    margin-left: 10%;
    float: left;
    background-color: antiquewhite;

}
#div1{  /*第一层*/
    width: 80%;
    height: 100%;
    margin-left: 10%;
    float: left;
    border: 3px brown double;
    background-color: rgba(0, 255, 140, 0.79);
}
#div2{
    width: 80%;
    margin-left: 10%;
    margin-top: 10%;
    margin-right: 10%;
    background-color: #ff0000;
    border: black ;
}
#tbl1{
    width: 60%;
    line-height: 30px;
    margin-top: 5%;
    margin-left: 20%;
}
#tbl1,#tbl1 tr,#tbl1 td{
    border: 1px solid olivedrab;
    border-collapse: collapse;
}